The investigator's plan is to evaluate the short-term and longer-term efficacy of three non-pharmacologic treatments for insomnia: (1) a behavioral treatment that uses the principles of sleep hygiene (HYG) in addition to timed exposure to a placebo light, (2) HYG plus timed bright light exposure in the morning (HYG+AM LIGHT), and (3) HYG plus timed bright light exposure in the afternoon (HYG+PM LIGHT). Hypotheses are: (1) Efficacy: bright light therapy will have a significant additive effect when combined with sleep hygiene compared to sleep hygiene alone. Primary outcome measures will be basic sleep parameters as recorded by actigraphy with subsidiary analyses using polysomnography (PSG). It is expected that improvement will be present at the end of the 3-month treatment and over a 3-month follow-up. (2) Individual Differences in Response (Moderators): There will be individual differences in the efficacy of the two HYG+LIGHT groups depending on the phase, amplitude, or the degree of synchronization of circadian rhythm measures demonstrated prior to treatment. It is also expected that genetic markers such as the human CLOCK gene, found to be associated with relative morning versus evening preference, may influence treatment response of insomnia patients receiving bright light either in the morning or in the evening. To test this hypothesis, individual baseline markers of circadian rhythms will be assessed as well as CLOCK allele status. (3) Mechanism of Action (Mediators): Changes in the phase, amplitude, or degree of synchronization of circadian rhythm measures over treatment may account for some of the observed effects of treatment. To test this hypothesis, changes during treatment of markers of circadian rhythms will be assessed in related to changes in sleep during treatment. (4) Quality of Life: The research will determine whether bright light is an effective therapy for insomnia relative to HYG in terms of its impact on health-related quality of life. These hypotheses will be tested in a parallel-groups design with three conditions: HYG, HYG-AM LIGHT, and HYG+PM LIGHT. Daily treatments will last three months and after the end of treatment patients will be followed on a once-a-month basis for a period of three months. Measures will be taken prior to the beginning of treatment, at the end of treatment, and to document stability of treatment effect, some measures will be repeated once a month during the three-month follow-up period. This five-year application will ultimately include 90 treatment subjects aged >60 years (three groups of 30 each).